Pliers having a rack and pawl coupling to produce greater force after the jaws closeabout the work



y 1966 w. D. BENTLEY, JR 3,253,437

PLIERS HAVING A RACK AND PAWL COUPLING TO PRODUCE GREATER FORCE AFTERTHE JAWS CLOSE ABOUT THE WORK Filed June 9, 1964 INVENTOR.

ma D. BEA/72.5), Lle. E/4m Mf r1 United States Patent PLIERS HAVING ARACK AND PAWL COUPLING This invention relates to hand tools andparticularly to pliers adapted to exert very high clamping pressure onthe work.

One known device of this character has been marketed for many yearsunder the trade mark Vise Grip. This device includes a trapezoid linkagewith two of the links being formed as parts or extensions of opposed jawmembers and the other two links forming elements of a toggle. Themaximum mechanical advantage occurs when the toggle links are inalignment, and this corresponds to adefinite relative angular positionof the jaw links and, hence, a definite separation of the jaw members.But the size of the work determines the separation of the jaw members.Hence, unless the toggle linkage is adjustable, the toggle links will beout of alignment when the work is engaged. Accordingly, the effectivelength of one of the links is subject to adjustment, as by manipulationof a knurled screw. A manipulation is also required to break the toggle.These manipulations are tedious and time consuming.

It is thus the primary object of this invention to provide a hand toolof this character that need not be adjusted according to the size of thework, but which yet applies a uniformly high clamping pressure thereto.For this purpose a handle is pivotally connected to one of two pivotallyconnected jaw members and yieldingly held by light, return-spring at onerelative angular position. A companion handle is formed as an extensionof the other jaw member. The jaws are caused to engage the work bymovement of the handles together; continued movement of the handleoverpowers the light return spring. A high mechanical advantage linkagethen automatically becomes operative between the pivoted handle and thejaw member joined to the opposite handle and high clamping pressure isexerted. When the grip on the handles is released, the coupling isdisengaged.

Another object of this invention is to provide a simple tool of thischaracter that can be economically manufactured.

V This invention possesses many other advantages, and

has other objects which may be made more clearly apparent from aconsideration of one embodiment of the invention. For this purpose,there is shown a form in the drawings accompanying and forming a part ofthe present specification, and which drawings are true scale. This formwill now be described in detail, illustrating the general principles ofthe invention; but it is to be understood that this detailed descriptionis not to be taken in a limiting sense, since the scope of thisinvention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a pictorial view of a hand-tool incorporating the presentinvention;

FIG. 2 is an enlarged fragmentary sectional view taken along a planecorresponding to line 22 of FIG. 1;

FIG. 3 is a front elevational view of the tool;

FIG. 4 is a fragmentary sectional view taken along a plane correspondingto line 4 -4 of FIG. 2; and

FIG. 5 is a fragmentary elevational view similar to FIG. 2 butillustrating the parts in a clamping position.

The tool shown in FIG. 1 comprises two mutually Patented May 31, 1966pivoted plier elements. One of the elements made as a single part hasends with an intermediate pivot plate 12, a jaw member 13 at one end anda handle 14 at the other. The companion plier element has two mainparts, a link 15 and a handle 16. The link 15 includes a pair of spacedparallel, flat, generally rectangular plates 17 and 18. These plates 17and 18 are integrally joined at corresponding ends to the base of a jawmember 19 to form a yoke.

The plates 17 and 18 receive the circular pivot plate 12 of thecompanion plier element. A suitable pin 20 adjacent the base of both jawmembers determines their path of relative angular movement. The pivotplate 12 extends well into the yoke formed by plates 17 and 18, theouter arcuate edge 12a of the pivot plate 12 extending approximatelyacross the central area of the yoke plates 17 and 18.

The handle 16 has a flattened end 21 that fits into the outer end of theyoke well beyond the pivot plate 12. A pin 22 connects the handle 16 tothe link 15 for movement about an axis parallel to the axis of movementof the jaw members.

The handle 16 and link 15 normally move in unison. For this purpose, anoverrunning coupling is effected between the link 15 and the handle 16.Movement of the handle 16 in a clockwise direction about the axis of thepin is limited. The handle 16 is yieldingly held at this limitedposition illustrated in FIG. 2. When the handles 14 and 16 are movedtogether, the jaw members 13 and 19 close about the work.

A bracket 23, welded as at 24 across the yoke, mounts a spring 25 thaturges the handle to the FIG. 2 position. The bracket 23 has an offsetend defining, at the side edges of the yoke, a space in which one end ofthe spring 25 is held. The outer free end of the spring 25 engages theouter end of a lug 26.

The lug 26 which is accommodated between the yoke plates 17 and 18 ispivotally connected to the handle end 21. Thus the lug has a roundedinner end that seats in a semi-circular recess 27 located at the edge ofthe handle end 21. One side of the recess or seat 27 is adjoined by anextended flat wall 28 that limits angular movement of the lug 26 in acounterclockwise direction, while the other side of the semi-circularseat or recess 27 is adjoined by a curved wall 29 that permits clockwisemovement of the lug.

The leaf spring 25 acts upon a flat end surface 26a of the lug 26 thatis accessible at the side of the yoke. The surface 26a extends at anangle of approximately 30 to a radial line from the lug axis x.Accordingly, the force exerted by the spring 25 on the lug 26 has asmall component that tends to rotate the lug in a clockwise directionabout the recess axis. A guide pin 30 extending through the yoke betweenthe handle end 21 and the pivot plate edge 12a engages the side of thelug 26 and limits clockwise angular movement. The spring 25 thus keepsthe lug against the pin 30. The force imposed by the spring 26 upon theflat surface 26a, however, also has a large radial component directedtoward the axis of the recess 27. This component tends to rotate thehandle 16 in a clockwise direction about its pin 22. The manner in whichthese force components act upon the handle 16 may be explained withreference to FIG. 5. In this position, the lug 26 is seated in therecess 27 but spaced from the fiat side surface 28 thereof. The spring25 holds the lug against the guide pin 30. Absent restraining torque onthe handle 16, the spring 25 acting through the lug 26 will rotate thehandle 16 in a clockwise direction about the pin 22. As the handle 16rotates in this direction, the guide pin 30 prevents the lug 26 fromrotating therewith. Accordingly, the lug is caused to rotate about theaxis of the recess 27. Ultimately the flat side surface 28 is engagedand the parts assume the position illustrated in FIG. 2. Should the link15 be restrained and a counterclockwise torque exerted upon the handle16 with the parts in the position of FIG. 2, the pawl 26 will be crankedoutwardly toward the pivot plate 12 due to the location of the guide pin30. This cranking movement of the lug 26 is used for the purpose ofcoupling the handle 16 to the opposite jaw member 13 for the impositionof substantial torque thereon.

Thus when the handles 14 and 16 are moved together with the handle 16 atits limited position, the jaw members 13 and 19 first close about thework W. Continued torque on the handle 16 causes the handle to moveangularly in a counterclockwise direction about the pin 22. The lug 26then moves to the position of FIG. and its corner 31 engages teeth 32formed in the edge 12a of the pivot plate 12. Since the crank has arelatively short lever arm about the axis of the pin 22, the mechanicaladvantage is substantial, and a clamping pressure of high magnitude isimposed upon the work.

The teeth 32 formed in the edge of the pivot plate 12 extend along anextended are centered at the pin 20. Accordingly, at whatever point thejaws 13 and 19 first engage the work, one of the teeth 32 is in positionto be engaged by the corner 31 of the lug 26.

As soon as the grip on the handles 14 and 16 is released, the spring 25returns the handle 16 to the position illustrated in FIG. 2 and the workmay be removed.

The inventor claims:

1. In a hand tool cooperable with a workpiece: a pair of jaw members;handles for the jaw members respectively; means operative independentlyof the workpiece and carried by the jaw members to confine the jawmembers for movement in a fixed path; movement of said jaw members inopposite directions in said fixed path causing opening and closingmovement of said jaw members; means forming an overrunning connectionbetween one of the handles and its jaw member; yielding spring meansnormally holding the handle against overrunning movement whereby saidone handle and its jaw member move as a unit relative to said other jawmember and its handle until relative movement of the jaw members isrestrained by contact with the work, whereupon said one handle memberbegins its overrunning movement and causes energy to be stored in saidspring means; and a releasable coupling between said one handle and theopposite jaw member for applying a closing force between the jawmembers, said coupling being established upon overrunning movement ofsaid one handle substantially independently of the relative position ofsaid jaw members.

2. In a hand tool: a first tool part having a central pivot plate, saidfirst tool part having a jaw member and a handle at opposite ends of thepivot plate; a second tool part having a yoke, and a jaw memberextending from the base of the yoke, said second tool part having ahandle, one end of the handle being received in and pivoted to the outerend of the yoke; said pivot plate being received in the yoke in inwardlyspaced relationship to said pivoted handle; a pin connecting the pivotplate to the yoke; said pivot plate having an edge extending arcuatelyabout said pin and opposed to said pivoted handle end; there beingratchet type teeth formed in said arcuate edge; a pawl having a roundedend; said lever end having a recess receiving the rounded pawl end, saidrecess extending inwardly of the edge of said lever end; said recesshaving one side extended to limit angular movement of the pawl about theaxis of the recess; a stop pin carried by the yoke and engaging the pawlto limit angular movement of the handle; a leaf spring engaging the pawland urging the pawl to seat in its recess and to move the pivoted leverto a limited position determined by said extended side and said stoppin; said pawl being cranked outwardly to engage said toothed edge uponangular movement of the lever away from its limited position wherebyclamping torque is applied by movement of said pivoted handle.

3. The combination as set forth in claim 1 in which said means operativeto confine the jaw members in a fixed path comprises a pivot pin carriedby one of the jaw members cooperable with an aperture formed in theother of the jaw members, the aperture having a configuration operativeto confine the jaw members for relative arcuate movement about saidpivot pin as an axis.

References Cited by the Examiner UNITED STATES PATENTS 1,207,947 12/1916Litchfield 81-314 2,413,178 12/1946 Feltman 81-314 X 2,720,900 10/1955Quist 81-364 X 3,169,307 2/1965 Langwell 81-314 X FOREIGN PATENTS 80,5455/1934 Sweden.

WILLIAM FELDMAN, Primary Examiner.

MILTON S. MEHR, Examiner.

1. IN A HAND TOOL COOPERABLE WITH A WORKPIECE: A PAIR OF JAW MEMBERS;HANDLES FOR THE JAW MEMBERS RESPECTIVELY; MEANS OPERATIVE INDEPENDENTLYOF THE WORKPIECE AND CARRIED BY THE JAW MEMBES TO CONFINE THE JAWMEMBERS FOR MOVEMENT IN A FIXED PATH; MOVEMENT OF SAID JAW MEMBES INOPPOSITE DIRECTIONS IN SAID FIXED PATH CAUSING OPENING AND CLOSINGMOVEMENT OF SAID JAW MEMBERS; MEANS FORMING AN OVERRUNNING CONNECTIONBETWEEN ONE OF THE HANDLES AND ITS JAW MEMBER; YIELDING SPRING MEANSNORMALLY HOLDING THE HANDLE AGAINST OVERRUNNING MOVEMENT WHEREBY SAIDONE HANDLE AND ITS JAW MEMBER MOVE AS A UNIT RELATIVE TO SAID OTHER JAWMEMBER AND ITS HANDLE UNTIL RELATIVE MOVEMENT OF THE JAW MEMBERS ISRESTRAINED BY CONTACT WITH THE WORK, WHEREUPON SAID ONE HANDLE MEMBERBEGINS ITS OVERRUNNING MOVEMENT AND CAUSES ENERGY TO BE STORED IN SAIDSPRING MEANS; AND A RELEASABLE COUPLING BETWEEN SAID ONE HANDLE AND THEOPPOSITE JAW MEMBER FOR APPLYING A CLOSING FORCE BETWEEN THE JAWMEMBERS, SAID COUPLING BEING ESTABLISHED UPON OVERRUNNING MOVEMENT OFSAID ONE HANDLE SUBSTANTIALLY INDEPENDENTLY OF THE RELATIVE POSITION OFSAID JAW MEMBERS.